. 190 NATURAL HISTORY. 



308. You see, then, that the brain, muscles, and other 

 organs in the Reptile are stimulated with the mixture, 

 which is not so stimulating or life-giving as pure arterial 

 blood. It is therefore a less lively animal than those 

 whose organs have arterial blood continually pumped 

 into them by the heart. It therefore moves but little and 

 slowly. Its circulation is slow, and so also is its breath- 

 ing. 



309. But, while life is dull in reptiles, it is not easily de- 

 stroyed. They will bear being maimed to a great ex- 

 tent. If you destroy the brain or spinal cord of a warm- 

 blooded animal, all signs of life soon cease ; but if this be 

 done to a reptile, motions can be excited for a long time 

 by pricking, or other modes of stimulation. The limbs 

 of a turtle which has been dead for several days may be 

 made to move by pricking them, showing that there is 

 some life in their muscles still. So, also, the two parts 

 of a snake cut in two will move independently for some 

 time, and the tail of a lizard will move for some hours 

 after it is cut off. The reptiles of temperate climates 

 crawl into some secret place as winter comes on, and go 

 into a state of perfect torpor which lasts till spring. They 

 are therefore called hibernating animals. 



310. The brain of reptiles is very small, for "they have 

 but little thinking to do. They have no special organ of 

 touch, and their covering is such that they can have but 

 little sensibility in it. The sense of taste and that of 

 smell are dull. Vision is not very acute, and the appa- 

 ratus of hearing is much less complete than in the warm- 

 blooded animals. 



311. Almost ah 1 reptiles are carnivorous. The turtles 

 and crocodiles divide their food more or less with their 

 jaws; but the snakes or serpents swallow their food 

 whole. In their case the throat can be so much dilated 

 that they can swallow an animal larger than themselves. 



312. Reptiles are like birds in two things : they do not 

 suckle their young, and they produce them from eggs. 



